- Porphyria variegate
- Porphyria, South African type
- PPOX deficiency
- Protoporphyrinogen oxidase deficiency
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Variegate porphyria is caused by mutations in the PPOX gene. Mutations in the PPOX gene reduce the activity of protoporphyrinogen oxidase, allowing compounds called porphyrin precursors to build up in the body. These compounds are formed during the normal process of heme production, but reduced activity of protoporphyrinogen oxidase allows them to accumulate to toxic levels. More than 130 mutations in the PPOX gene have been identified in people with variegate porphyria. A particular PPOX gene mutation is found in about 95 percent of South African families with the disorder.
Nongenetic factors such as certain drugs, alcohol, dieting, as well as other genetic factors that have not been identified, also contribute to the characteristic features of variegate porphyria.